HDMI with analog audio inputs?

I know I'm missing something obvious here, but maybe I just haven't had enough coffee yet.

I noticed that on the connections for the Panny plasma I'm planning to buy, the HDMI input also comes with two analog audio inputs alongside it. I know HDMI supports multiple audio signal types, including plain stereo and multichannel surround. So why these accompanying and separate audio input jacks?

Speaking of mixing HDMI and other audio inputs, I have a configuration question.

My home theater receiver does component video in and digital audio in (coax and optical), but not HDMI. My new DVD player has HDMI, but obviously I'd want to run playback through my receiver for movie surround sound and for music. Is it worth it to run HDMI from the DVD player to the TV just for video or is component equivalent? I've read about so many headaches with HDMI that I'd like just to use component if I can't take advantage of the audio capabilities of HDMI and I'm going to get comparable picture quality with the component.

99% of DVD players can only upconvert to HD via HDMI/DVI, so you have to use it for upconversion. Otherwise, there isn't much difference in quality HDMI vs component, but I imagine it varies from player to player.